pg_upgrade: avoid failing if tablespace dirs exist and are empty

When Who What
2020-10-27 02:44:50 Justin Pryzby (justinpryzby) Closed in commitfest 2020-11 with status: Rejected
2020-10-24 00:26:34 Justin Pryzby (justinpryzby) Added annotation "The earlier patches in this thread caused --check to notice a failure. The v3 patch now (also) sometimes avoids the failure altogether" to 20201021115416.GK9241@telsasoft.com
2020-10-24 00:24:55 Justin Pryzby (justinpryzby) Changed authors to Justin Pryzby (justinpryzby)
2020-10-24 00:24:55 Justin Pryzby (justinpryzby) Changed targetversion to 14
2020-10-24 00:24:39 Justin Pryzby (justinpryzby) Attached mail thread 20200925005531.GJ23631@telsasoft.com
2020-10-24 00:24:39 Justin Pryzby (justinpryzby) Created patch record